Conventionally, paper rolls are packaged by first placing the inner headers onto the roll ends, followed by enveloping the roll in a desired number of wrapper convolutions, whereby the wrapper overlap can be crimped over the inner headers placed abutting the roll ends. Alternatively, the wrapper can be wrapped first, followed by insertion of the inner headers into the tubes formed by the wrapper overlap at the roll ends. Next, the wrapper rims are crimped against the roll end, and the outer header is attached onto the crimped wrapper rim and the underlying inner header using conventional hot-melt glueing. Generally, the inner header is made from a relatively thick material thus offering protection to the roll end from mechanical damage. The outer header in turn is made from a thinner material used to bind the wrapper at the roll end and to protect the roll against moisture. Frequently, the colors and pattern printed on the outer header aim at a neat look of the wrapped roll.
A plurality of methods can be used for placing headers onto the roll ends. Manual placing is the oldest technique and it is still suitable for use on packaging lines of relatively modest capacity or in applications manageable without a major need of improving the degree of automation. Herein, the operator simply manually places the inner headers to the roll ends and, positions the outer headers on heatable press platens which attach the outer headers to the roll ends. During the crimping of the wrapper overlap, the inner headers are held by means of separate support arms abutting the roll ends. A vacuum suction is used in turn to keep the outer headers in place on the press platens.
Various designs of automatic header inserters based on different approaches have been used in the art for quite a long time. Common to almost all automatic inserters is that the inserter equipment incorporates for either end of the roll a manipulator device equipped with a grabber capable of transferring the header from a header stack to the roll end. Movably mounted on a vertical guide, a prior-art header inserter has a rotatable arm with a vacuum grabber at its distal end for grasping the headers. Such a header inserter is generally used so that it is adapted to cooperate with different types of header storage shelves located close to the header inserter. By means of this equipment, headers are placed on the roll ends so that the picker arm is first moved along the vertical guide to the height of the shelf containing the stack of desired size headers. Next, the picker arm and the grabber are rotated until the grabber is located parallel to the stack top on the shelf, after which the desired header is picked from the stack and, by rotationally moving the grabber and the arm as well as sliding the same along the vertical guide, transferred to the roll end.
In another system, the headers are placed in stacks on the plant floor and transferred therefrom to the roll ends by means of portal header manipulators. The portal-type transfer manipulator is mounted above the header stacks and the header inserters are generally positioned on the same transferrable crosswise spanned beam. Hence, a separate stack or stacks of each size of headers must be provided for the grabber.
In U.S. Pat. Nos. 4,744,198 and 4,840,008 are disclosed a system for inserting headers where the rolls are first wrapped with a wrapper prior to the insertion of the inner headers. In this system, the headers of different sizes are placed in stacks on tilted shelves. In front of the shelves is a positioning platen movable in the vertical direction. During the fetching of the headers, the positioning platen is elevated to the level of the shelf supporting the desired type of headers and the header is transferred from the shelf stack onto the positioning platen. The locating stops of the platen align the header into its correct position, therefore the header is then moved by means of a pusher to an inserter which in turn pushes the header into a tube formed at the roll end by the wrapper overlap and further fully home against the roll end. As this packaging method requires accurate positioning of the header with respect to the center of the wrapper tube and further against the center of the roll end, the header must be prelocated very precisely prior to its insertion. This prelocation step is performed on said positioning platen and the headers are transferred from said platen along an accurately controlled trajectory to the roll end thus assuring that the prelocation of the header position on the positioning platen corresponds to the desired inserted position of the header on the roll end. Further, as the roll diameters may vary widely, the header inserter device performing the transfer of the headers to the roll ends must have a design compatible with headers of different sizes. In the equipment disclosed in the above-cited patents, this requirement is implemented so that the header inserter has a number of suction cups, of which at least some can be moved into a different position with respect to the other suction cups. In this manner, the headers may be grabbed always sufficiently close to their edges, thus protecting the headers against folding during the placement of the header against the roll end, and moreover, the header inserter can be adapted to fit into the end cavities of the wrapper tube also with smaller-diameter header sizes.
In the above-described, the header inserters are located at both ends of the roll so that the inserters are aligned coaxially with the roll and adapted to move linearly along the center axis of the roll. This arrangement may cause functional disturbances especially in conjunction with thin wrappers. In some situations, the wrapper may sag under its own weight slightly downward, whereby the cross-sectional shape of the tubular cavity formed by the wrapper overlap deviates from the circular shape of the roll outer diameter. As a result, the header edge may hit the wrapper during insertion, thus damaging both the wrapper and header. In order to avoid damages, the function of the equipment must be monitored carefully, and in malfunction situations, the equipment must be stopped and the headers must be placed manually after the wrapper rim is straightened. The header inserter structure becomes rather complicated with the movable suction cups, which require separate mechanisms for moving the suction cups both radially relative to each other and axially with respect to the roll end. This construction is not suited for use in packaging systems in which the roll is rolled into the header inserter station and away therefrom from the side of the station, because the roll cannot obviously be transferred to the station in the direction of the longitudinal axis of the roll. Hence, this type of header inserter station requires a large footprint and restricts the modifiability of the packaging system for use in different applications.